Once because 5 times 1 is 5 and that's closest it will go into Hope that helped Have a good day! :-)
Y = -8x - 5/4......slope here is -8 or -8/1
y = 1/8x + 4/5...slope here is 1/8
what u have here are negative reciprocal slopes....negative reciprocal of a number can be found by flipping the number and changing the sign. So the negative reciprocal of -8/1 is 1/8 (see how I flipped the number and changed the sign)...and when u have negative reciprocal slopes, this means that ur lines are perpendicular.
10/14 = 5/7 in simplest form